What is the typical dose of Keflex (Cephalexin) for treating cellulitis?

From the Guidelines

For treating cellulitis in adults, the typical dose of Keflex (cephalexin) is 500 mg taken orally every 6 hours, or alternatively 1 gram every 12 hours, for 5-6 days depending on the severity of the infection. This recommendation is based on the most recent and highest quality study available, which suggests that a 5- to 6-day course of antibiotics active against streptococci is sufficient for patients with nonpurulent cellulitis 1.

Key Considerations

• The duration of treatment may be extended if the infection is severe or slow to respond.
• Patients should complete the entire prescribed course even if symptoms improve before finishing the medication to ensure complete eradication of the infection.
• Keflex works by inhibiting bacterial cell wall synthesis, making it effective against many of the common skin pathogens that cause cellulitis, particularly Streptococcus and Staphylococcus species.
• It's essential to take the medication with food if it causes stomach upset, stay well-hydrated, and elevate the affected area when possible to help reduce swelling.
• If symptoms worsen or don't improve within 48-72 hours, patients should contact their healthcare provider as this may indicate the need for a different antibiotic or additional treatment.

Additional Guidance

• For children, the dosage is typically 25-50 mg/kg/day divided into four equal doses.
• The 2014 IDSA guideline recommends that patients should receive antibiotics for uncomplicated cellulitis, but the duration of treatment may vary depending on the severity of the infection 1.
• More recent studies suggest that shorter courses of antibiotics, such as 5-6 days, may be effective for treating cellulitis, especially for patients who are able to self-monitor and have close follow-up with primary care 1.

From the FDA Drug Label

For the following infections, a dosage of 500 mg may be administered every 12 hours: streptococcal pharyngitis, skin and skin structure infections, and uncomplicated cystitis in patients over 15 years of age. The typical dose of Keflex (Cephalexin) for treating cellulitis is 500 mg every 12 hours 2.

• The dose may be adjusted based on the severity of the infection.
• For more severe infections, larger doses may be needed.
• If daily doses of cephalexin greater than 4 g are required, parenteral cephalosporins should be considered.

From the Research

Keflex Dose for Cellulitis

• The typical dose of Keflex (Cephalexin) for treating cellulitis is not explicitly stated in the provided studies, but we can look at the dosages used in similar contexts:
  • In the study 3, cephalexin was given at a dose of 500 mg 4 times daily for 7 days.
  • The study 4 mentions flucloxacillin, a different antibiotic, at a minimum of 500 mg 4 times per day for 5 days, but this is not directly applicable to cephalexin.

Considerations for Treatment

• The choice of antibiotic and dosage may depend on various factors, including the severity of the cellulitis, the presence of methicillin-resistant Staphylococcus aureus (MRSA), and patient-specific considerations such as renal function and potential allergies.
• Studies 5 and 3 suggest that antibiotics with activity against MRSA, such as trimethoprim-sulfamethoxazole, may be preferred in certain cases, but the evidence is not conclusive.
• The duration of treatment is also a consideration, with some studies 6 and 7 suggesting that shorter courses of treatment (5-7 days) may be as effective as longer courses (10 days).

Adverse Effects and Interactions

• The addition of clindamycin to flucloxacillin was found to increase the likelihood of diarrhea in one study 4.
• The study 3 found no significant difference in adverse event rates between cephalexin plus trimethoprim-sulfamethoxazole and cephalexin alone.